PH1125 - carbohydrates Flashcards
1
Q
what are glycosides?
A
- molecules with a sugar and non-sugar component
2
Q
how are sugars biosynthesised? (2)
A
- by plants from CO2 and H2O
- using energy from the sun
3
Q
what are the functions of carbohydrates? (4)
A
- energy storage in plants (starch) and human (glycogen)
- structural components (chitin cell walls)
- fundamental componens of coenzymes (NAD, ATP), DNA, RNA
- signalling molecules when conjugated to protein and lipids
4
Q
what atoms do carbohydrates contain? (3)
A
- carbon
- hydrogen
- oxygen
5
Q
what is the empirical formula for carbohydrates?
A
Cm(H2O)n
6
Q
what are the two stereochemical forms of carbohydrates? (2)
A
D or L
7
Q
what is a monosaccharide?
A
- single carbohydrate monomer
8
Q
what forms do rings exist in?
A
- alpha and beta anomers
9
Q
what happens in distilled water at room temperature?
A
- alpha/beta anomers interconvert to form a mixture
10
Q
what is maltose? (2)
A
- disaccharide
- two D-glucose monomers
11
Q
what is the link between single sugars called?
A
- glycosidic bonds (classified according to the atoms they link)
12
Q
what is lactulose? (4)
A
- osmotic laxative
- not a naturally occurring sugar and manufactured synthetically
- causes water to accumulate in the colon and softens stool
- example of a drug with than unusual mode of action with no target
13
Q
what is digoxin?
A
- it is a cardiovascular drug used for heart failure and other CV conditions
14
Q
what happens in phase 2 metabolism?
A
- drugs are conjugated with glucuronic acid
15
Q
what is cellulose?
A
- polysaccharide of many D-glucose monomers
- beta 1,4 glycosidic bond
